C. A 1200kg car is going 15m/s
Answer:
Option A. 1 bar = 1 atm
Explanation:
Pressure has various units of measurement. Each unit of measurement can be converted to other units of measurement. For example:
1 atm = 1 bar
1 atm = 760 mmHg
1 atm = 760 torr
1 atm = 1×10⁵ N/m²
1 atm = 1×10⁵ Pa
With the above conversion scale we can convert from one unit to the other.
Considering the question given above, it is evident from the coversion scale illustrated above that only option A is correct.
Thus,
1 bar = 1 atm
Solution :
Given :
Rectangular wingspan
Length,L = 17.5 m
Chord, c = 3 m
Free stream velocity of flow,
= 200 m/s
Given that the flow is laminar.



So boundary layer thickness,


= 0.0024 m
The dynamic pressure, 


The skin friction drag co-efficient is given by


= 0.00021


= 270 N
Therefore the net drag = 270 x 2
= 540 N
Seismograph is the correct answer